qmemman: switch off memory balancing when doing xm save

Apparently, it interferes:
INFO (XendCheckpoint:417) ERROR Internal error: Could not get vcpu context
INFO (XendCheckpoint:417) ERROR Internal error: Failed to map/save the p2m frame list

dom0/qmemman/qmemman.py

@@ -140,7 +140,7 @@ class SystemState:
         return total_memory_transfer > MIN_TOTAL_MEMORY_TRANSFER
 
     def do_balance(self):
-        if os.path.isfile('/etc/do-not-membalance'):
+        if os.path.isfile('/var/run/qubes/do-not-membalance'):
             return
         self.refresh_memactual()
         xenfree = self.get_free_xen_memory()

dom0/restore/qubes_prepare_saved_domain.sh

@@ -48,10 +48,16 @@ xenstore-read /local/domain/$ID/qubes_gateway | \
 xm block-detach $1 /dev/xvdb
 MEM=$(xenstore-read /local/domain/$ID/device/qubes_used_mem)
 echo MEM=$MEM
+QMEMMAN_STOP=/var/run/qubes/do-not-membalance
+touch $QMEMMAN_STOP
 xm mem-set $1 $(($MEM/1000))
 sleep 1
 touch $2
-if ! xm save $1 $2 ; then exit 1 ; fi
+if ! xm save $1 $2 ; then 
+	rm -f $QMEMMAN_STOP
+	exit 1
+fi
+rm -f $QMEMMAN_STOP
 cd $VMDIR
 tar -Scvf saved_cows.tar root-cow.img swap-cow.img